Method for increasing puncture resistance of a waterproof membrane

ABSTRACT

A method for increasing puncture resistance of a thermoplastic or elastomeric membrane for use in water proofing of subterranean structural substrates, the method comprising bonding a layer of cushion material to the membrane, the cushion material comprising a cellular foam material and being adapted to conform around minor irregularities in a surface of the structural substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a division of application Ser. No. 11/881,245, filed Jul. 26, 2007 in the names of Brian J. Whelan, Gary W. Whittemore, Dan Ben-Daat and Jon M. Jensen. This application claims priority from U.S. Provisional Patent Application No. 60/856,155, filed Nov. 2, 2006, and U.S. Provisional Application No. 60/934,785, filed Jun. 15, 2007, both filed in the names of Brian J. Whelan, Gary W. Whittemore, Dan Ben-Daat, and Jon M. Jensen.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to a self-adhering membrane which may be applied to roof and/or wall structures, particularly “green” roof and plaza deck constructions, including planters, balconies, terraces, foundation walls, tunnel structures, and the like.

2. Description of the Prior Art

It has become increasingly popular to provide new building and other constructions with green roofs, that is, roofs supporting earth, grass, and plantings, often with walk-ways and/or terraces. The roof decks frequently are made of structural concrete or metal decking covered with a rigid hardboard, sometimes metal-covered, and covered with a water-proof thermoplastic membrane applied to the outside surface of the concrete, rigid hardboard, or other substrate. Inasmuch as the membrane is typically of the type customarily used on conventional non-green rooftops, and having a thickness of about 60 or more mils, the membrane must be applied to a very smooth and clean concrete, rigid hardboard, or other rigid surface. Irregularities in the smoothness of the outside surface of the substrate can produce perforations and punctures in the membrane which breach the water-tight integrity of the membrane. The same problem applies to foundation walls, tunnel structures, and the like, of structural concrete or masonry.

In an effort to better absorb and conform to irregularities in the substrate surface, a layer of felt-like material has been used to form a cushion layer of sorts between the substrate surface and the waterproof membrane. However, it has been discovered that while perforations and punctures in the membrane are reduced, any that remain or occur allow water passing therethrough to flow into the felt-like material which acts like a wick and spreads the water out in directions not easy to determine. Because of lateral migration of the water, a leak in the membrane in a first area may make itself known in remote second areas. Determining the location of the leak into the underlying structure can be extremely difficult, expensive and time-consuming to accomplish, inasmuch as removal of the overburden is required to gain access to a breach in the membrane.

To overcome the above-noted problems, resort has been made to adhered liquid materials, such as hot rubberized asphalt (HRA), a system which, as the name implies, involves the laying down of HRA in the form of a hot liquid, usually of about 150-215 mils thickness. In such procedures, precautions must be taken with respect to workers inhaling fumes, handling hot kettles, and the hot asphalt. The odor and smell of asphalt tends to travel and irritate nearby site workers, building occupants and general public. Further, usually no portion of the area can be used during installation of HRA nor after installation until the HRA cools and solidifies.

Cold-applied liquid products are also used in such applications, best installed in thinner coatings of around 60 mils thickness. Such materials have fewer application issues inasmuch as they are applied at ambient temperatures, but often contain solvents which have odors and repugnant smells, or, when spray-applied, produce air-borne particulates that create a potential hazard for installers, site workers, and building occupants.

Thus, there is a need for an effective, efficient, less expensive, odor and solvent-free, and less hazardous material and method for laying a waterproofing membrane down over a structure that is subject to a wet or moist external environment.

Accordingly, an object of the invention is to provide a waterproofing membrane for application to a surface of a structure to provide waterproofing and moisture protection to the structure, and which does not provide a medium for lateral migration of water therethrough.

A further object of the invention is to provide a method for making a waterproof membrane for application to a surface of a structure.

A further object of the invention is to provide a roof/wall, foundation or tunnel structure providing watertight integrity.

A still further object of the invention is to provide a method for waterproofing a roof and/or a wall, foundation or tunnel structure.

A still further object of the invention is to provide a method for increasing puncture resistance of a thermoplastic or elastomeric membrane for use in water proofing subterranean structures and surfaces.

SUMMARY OF THE INVENTION

With the above and other objects in view, as will hereinafter appear, a feature of the present invention is the provision of a membrane for application to a surface of a structure to provide waterproofing and moisture protection to the structure. The membrane includes an outer surface layer of thermoplastic material, a layer of cushion material laminated to, or fused to, or adhered to, an inner surface of the layer of thermoplastic material, a pressure sensitive adhesive bound to a side of the cushion material remote from the thermoplastic layer, and a release liner removably mounted on the remote side of the pressure sensitive adhesive.

In accordance with a further feature of the invention, there is provided a method for making a waterproof membrane, the method comprising the steps of providing a layer of cushion material, bonding a layer of waterproof thermoplastic material to a first side of the layer of cushion material, affixing a layer of pressure sensitive adhesive to a second side of the layer of cushion material, and mounting a release liner on a side of the pressure sensitive adhesive remote from the cushion material.

In accordance with a further feature of the invention, there is provided a roof/wall, foundation or tunnel structure (hereinafter “roof/wall”) comprising a substantially rigid substrate, and a laminar membrane adhesively bonded to an outer surface of the substrate. The membrane comprises an outer surface layer of thermoplastic material, a layer of cushion material bound to an inner surface of the layer of thermoplastic material, and a pressure sensitive adhesive bound to a side of the cushion material remote from the thermoplastic layer, and bound to the substrate.

In accordance with a still further feature of the invention, there is provided a method for waterproofing a structural surface. The method comprises the steps of providing a membrane for application to the surface, the membrane comprising an outer surface layer of thermoplastic material, a layer of cushion material laminated to, or fused to, or adhered to an inner surface of the layer of thermoplastic material, a pressure sensitive adhesive bound to a surface of the cushion material remote from the thermoplastic layer, and a release liner removably mounted on the remote side of the pressure sensitive adhesive, removing the release liner to expose the pressure sensitive adhesive, and pressing the pressure sensitive adhesive against the structural surface to conform the layer of cushion material to the structural surface and bind the waterproofing membrane to the structural surface.

In accordance with a still further feature of the invention, there is provided a method for increasing puncture resistance of a thermoplastic or elastomeric membrane for use in water proofing of subterranean structural substrates. The method comprises bonding a layer of cushion material to the thermoplastic membrane, the cushion material comprising a cellular foam material, the cushion material being adapted to conform around minor irregularities in a surface of the structural substrate.

The above and other features of the invention, including various novel details of construction, combinations of parts, and method steps, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular laminar combinations and methods embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the accompanying drawings in which are shown illustrative embodiments of the invention, from which its novel features and advantages will be apparent.

In the drawings:

FIG. 1 is a diagrammatic sectional view of one form of a portion of a waterproofing membrane illustrative of an embodiment of the invention; and

FIG. 2 is a diagrammatic sectional view of one form of a portion of a waterproofed roof/wall structure illustrative of a further embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, it will be seen that the illustrative waterproofing membrane 10 includes an outer surface layer 12 of thermoplastic waterproof material, such as vinyl or polyolefin, bonded to a cellular foam backing layer 14 coated with a pressure sensitive adhesive 16. The bonding of the backing layer 14 to the surface layer 12 may be accomplished by adhesive adhering, laminating, extrusion coating, heat sealing, gluing or taping, or the like. A manually removable release liner 18 is mounted on an undersurface 17 of the pressure sensitive adhesive 16 prior to application of the membrane 10 to a roof/wall structure 20 (FIG. 2).

The total composite membrane 10 may be about 120-140 mils or greater, in thickness, including the layer of waterproof material 12, which may be about 60 mils, or greater, in thickness, and the foam backing layer 14, which may be also about 60 mils, or greater, in thickness. Alternatively, the layer 12 may be 0.015-0.080 inch in thickness, and the backing layer 14 may be 0.015-0.375 inch in thickness, depending upon the particulars of a specific application or project.

The flexible foam backing 14 conforms around minor irregularities in the roof/wall structure 20. The pressure sensitive adhesive 16 provides a strong bond between the membrane 10 and the roof/wall structure 20, even in the presence of water and concrete alkalis.

The structure 20 typically is a green roof and/or a plaza deck serving as a roof structure for a work space or habitat therebeneath. Because of the heavy loads associated with such applications, the supporting deck 20 is most often structural concrete. The external environment for such roofs is generally at least damp and often subject to wetness, including pooling or ponding. The structure may also be a foundation wall or an earth sheltered structure or tunnel. The membrane 10 accordingly is designed to protect the structure 20 from the effects of water infiltration which can lead to structural deterioration and interior water damage.

In one embodiment, the outer surface layer 12 is a thermoplastic flexible sheet, made of vinyl or polyolefin, most commonly with an integral reinforcing material, such as glass fiber, polyester, nylon, or similar material. The backing layer 14 preferably is a cellular foam, such as a non-absorptive closed cell foam. The backing layer 14 is provided with the pressure sensitive adhesive 16 which is factory-applied and protected by the release liner 18 which is removed during application. The laminar membrane 10 has been found to substantially increase puncture resistance, compared to standard prior art membranes which do not include a backing layer.

Preferably, the surface layer 12 extends beyond a side edge 22 of the foam backing layer by about 2-4 inches to provide a selvedge 24. The membrane 10 is shown in width-wise cross section in FIGS. 1 and 2 and is typically provided in rolls which are 6.5-12.0 feet in width with, additionally, the 2-4 inch selvedge 24 on one side. In positioning the membrane 10 on the structure 20, the membrane sheets are disposed side-by-side with the foam backing layers 14 tightly abutting each other, and with the selvedge 24 overlapping the top of an adjoining membrane. The selvedge 24 is bonded, as by adhesives, glues, tapes, hot-air or solvent welding, to the overlapped membrane surface layer to provide bonded seams which will not deteriorate in the presence of water, moisture, roots, micro-organisms, and the like.

There is thus provided a waterproofing membrane which can be applied directly to concrete and other substances. The membrane finds particular application to green roof, plaza deck, planter, balcony and terrace substrates, foundation walls and tunnels, and is highly resistant to sub-grade environments of constant dampness, high alkalinity, exposure to plant roots, fungi, and bacterial organisms, as well as hydrostatic pressure, including ponded water conditions.

The membrane 10 is factory produced in its entirety. There is no assembly of the membrane at the work site; even the adhesive 16 by which the membrane 10 is applied to the structural substrate 20, is provided on the membrane and protected until the point of attachment by a readily removable release liner 18.

The membrane is made by providing the cellular foam backing, or cushion layer 14, of a selected length and width suitable for subsequent packaging in roll form. The layer of thermoplastic waterproof material 12 is bonded to a first side of the cushion layer 14. The layer of pressure sensitive adhesive 16 is deposited on a second side of the cushion layer 14, and the release liner 18 is mounted on the pressure sensitive adhesive 16 to completely cover the adhesive.

Preferably, the layer of thermoplastic waterproof material 12 extends beyond one side edge 22 of the cushion layer 14 to provide the aforementioned selvedge 24.

In the event of any incompatibility between the cushion material 14 and the pressure sensitive adhesive 16, a barrier film 26 may be interposed therebetween.

The assembled membrane components are then wound into roll form suitable for placing on a substrate and un-rolled on the substrate, while manually removing the release liner 18 to place the membrane 10, adhesive side down, on the surface of the substrate 20.

Upon application of the membrane 10 to the substrate 20, there is provided a roof/wall structure 30 (FIG. 2) including the substantially rigid substrate 20 and the waterproof membrane 10 adhesively bonded to an outer surface of the substrate, the membrane including the surface layer 12 of thermoplastic waterproof material, the layer 14 of cushion material bound to the surface layer 12, and the pressure sensitive adhesive 16 bound to a side of the cushion material 14 remote from the layer of thermoplastic waterproof material 12, and bound to the substrate 20.

The waterproof membrane surface layer 12 is in the form of an elongated strip which extends sideways outwardly from the side edge 22 of the layer 14 of cushion material to form the selvedge 24 (FIG. 1). The roof/wall structure includes a plurality of the strips of membrane 10 disposed on the substrate 20 lengthwise side-by-side with side edges 22 of their respective cushion portions 14 abutting each other, and the selvedge 24 of one elongated strip overlapping, and heat welded or otherwise adhered to, the surface layer 12 of another elongated strip of like structure.

The roof/wall structure thus formed is highly resistant to the aforementioned sub-grade environments.

There is further provided a method for waterproofing a structural surface. The method includes providing the waterproof membrane 10 for application to the surface, the membrane comprising the outer surface layer 12 of thermoplastic material, the layer of cushion material 14 bound to an inner surface of the layer of thermoplastic material, the pressure sensitive adhesive 16 bound to a side of the cushion material 14 remote from the surface layer 12 of thermoplastic material, and the release liner 18 removably mounted on the pressure sensitive adhesive 16.

The method includes the steps of removing the release liner 18 to expose the pressure sensitive adhesive 16, and pressing the pressure sensitive adhesive 16 against the structural surface to conform the layer of cushion material 14 to the structural surface 20 and bind the waterproofing membrane 10 to the structural surface.

The method for waterproofing the structural surface further comprises providing the layer 12 of thermoplastic material with a selvedge 24 comprising an extension of the outer layer of waterproof material 12 beyond a side edge 22 of the cellular foam cushion 14, preferably by about 2-4 inches. The selvedge 24 overlaps a neighboring strip of membrane, while the cushion portion 14 of the two strips are in abutting relationship. The selvedge is bound to the neighboring waterproof surface layer, as by heat-welding, adhesively, and the like.

Finally, there is provided a method for increasing puncture resistance of a thermoplastic membrane 10 for use in water proofing of structural substrates 20, the method comprising bonding a layer of cushion material 14 to the thermoplastic membrane 10, the cushion material 14 comprising a cellular foam material, the cushion material being adapted to conform around minor irregularities in a surface of the structural substrate 20.

There is thus provided a membrane for application to a surface of a structure to provide waterproof protection to the structure, a method for making such a membrane, a roof/wall structure including the membrane, a method for waterproofing a structured surface using the aforementioned membrane, and a method for providing increased puncture resistance to a thermoplastic membrane.

It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principles and scope of the invention as expressed in the appended claims.

For example, while the laminar structure described above is said to include a waterproof thermoplastic layer, and while such is regarded as a preferred embodiment, it will be apparent to those skilled in the art that a waterproof elastomeric material could also serve as a waterproof layer. 

1. A method for increasing puncture resistance of a selected one of a waterproof thermoplastic membrane and a waterproof elastomeric membrane for use in water proofing of subterranean structural substrates, the method comprising bonding a layer of cushion material to the waterproof membrane, the cushion material comprising a cellular foam material, the cushion material being adapted to conform around minor irregularities in a surface of the structural substrate.
 2. The method in accordance with claim 1 wherein the cushion material comprises a non-absorptive closed cell foam material.
 3. The method in accordance with claim 1, wherein the cushion material comprises a cellular foam material of at least about 0.015-0.375 inch thickness.
 4. The method in accordance with claim 3, wherein the layer of waterproof material extends on a side thereof beyond a side-edge of adjoining cushion material to form a selvedge, and comprising the further step of bonding the selvedge to an edge portion of an abutting layer of waterproof material of a second membrane.
 5. The method in accordance with claim 4, wherein the step of bonding the selvedge comprises bonding the selvedge to the edge portion of the abutting layer of waterproof material of the second membrane by a selected one of adhesive, glue and tape bonding and hot-air welding.
 6. The method in accordance with claim 1, wherein the step of bonding the layer of waterproof material to the layer of cushion material comprises a selected one of adhesively adhering, laminating, extrusion coating, heat sealing, gluing and taping of the waterproof material to the cushion material.
 7. The method in accordance with claim 1 wherein the waterproof membrane comprises at least one of vinyl and polyolefin. 